Reinnervation of experimental superficial wounds in rats

Sensory reinnervation of a superficial skin wound in the rat was studied by labeling sensory axons with anterogradely transported wheat germ agglutinin-horseradish peroxidase. Reinnervation starts after 3 days from the edge of the wound as well as from beneath the wound. About 2 weeks after the production of the wound, some hyperinnervation appears to be present, but after a few additional weeks, the innervation pattern is essentially normal. The results indicate that structural recovery of sensory axons is rapid and probably complete when skin wounds heal with no or minimal scar formation.     

Biomarker profiles in serum and saliva of experimental Sj?gren's syndrome: associations with specific autoimmune manifestations

Introduction  

Sj?gren's syndrome (SS) is a systemic autoimmune disease that mainly targets the exocrine glands. The aim of this study was to investigate the involvement of 87 proteins measured in serum and 75 proteins analyzed in saliva in spontaneous experimental SS. In addition, we intended to compute a model of the immunological situation representing the overt disease stage of SS.     

Estrogen accelerates immune complex glomerulonephritis but ameliorates T cell-mediated vasculitis and sialadenitis in autoimmune MRL lpr/lpr mice.

Estrogen is known to influence immune responses in healthy subjects in a dichotomous fashion. Thus, in number of previous studies we and others have demonstrated that B cell activities are augmented after exposure to estrogen whereas T cell reactivity is suppressed. Furthermore, it has been shown that this hormone has significant impact on the course of certain human and experimental autoimmune diseases. In this study we report that treatment with physiological doses of estradiol exerts dichotomous effects on different manifestations of the lupus disease in MRL/l mice. On one hand immune complex-mediated glomerulonephritis was significantly accelerated. This outcome was due to polyclonal B cell activation with increased production of antibodies to double-stranded DNA and formation of circulating immune complexes. In contrast, T cell-mediated lesions such as focal sialadenitis, renal vasculitis, and periarticular inflammation were all significantly ameliorated in MRL/l mice exposed to estrogen. Thus, we were able to demonstrate that, within one subject and even within one organ, administration of estrogen leads to differential outcome of SLE morbidity. We propose that the differential effect of estrogen on the manifestations of the autoimmune disease of MRL/l mice is due to its dichotomous effects on B and T cell-mediated immune responses.     

Misunderstanding as therapy: Doctors,patients and medicines in a rural clinic in Sri Lanka

In this paper I want to draw attention to the integration of Western medicine into therapeutic choices among patients in rural Sri Lanka. These patients' interpretation and use of Western pharmaceuticals is discussed in relation to the Ayurvedic theory of balance. The influence of this theory on people's ideas of health and illness is highlighted in encounters where laymen and professionals alike use Western medicines according to context and their respective perspectives. Such therapeutic encounters are used to describe how the meaning of therapy is negotiated and communicated. The modes of perception used by doctors and patients seem to be mutually exclusive but each has its own logic. Western medicines are used as a symbolic means which help the patients and the practitioners of Western clinical medicine in a rural health unit to communicate through — rather than despite — misunderstandings based on their differing cultural assumptions about the body, about disease and about therapy. This argument is raised in relation to recent theoretical discussions among medical anthropologists concerning doctor-patient relationships, asymmetric medical relations and the analysis of meaning systems     

Resource utilization of sympatric and experimentally allopatric cutthroat trout and Dolly Varden charr

Summary Resource utilization by cutthroat trout (CT) and Dolly Varden charr (DV) was studied 8 years after experimental transfers from sympatry had established reproducing allopatric populations in two nearby fishless lakes. Allopatric DV significantly increased their utilization of shallow-dwelling zoobenthos, and increased their vertical distribution in comparison to that in sympatry. In contrast, allopatric CT showed little change in the proportions of major prey types utilized, and, if anything, restricted their vertical distribution in comparison to that in sympatry. The results can be explained by the hypothesis that the resource use of DV is strongly influenced by interspecific competition from CT, whereas CT largely remains unaffected by this interaction. An alternative hypothesis, that lake differences can explain the differences in resource use between sympatry and allopatry, was evaluated by comparing food resource availability and other biotic and abiotic characteristics of the three study lakes. None of these could account for the shift in resource use by DV between sympatry and allopatry, but lake differences may explain why allopatric CT showed a restricted habitat use in comparison with their sympatric donor stock. The results of this whole-lake transfer experiment are consistent with earlier reported field and laboratory studies, and suggest that the aggressive dominance of CT is the most important mechanism by which DV are displaced from littoral and near-surface habitats in sympathy with CT.     

Variations in the cytoplasmic region account for the heterogeneity of the chicken MHC class I (B-F) molecules

Molecular variation among major histocompatibility complex (MHC) class I (B-F) proteins from B-homozygous chickens is apparently caused by C-terminal variation. Analysis of the total B-F protein pool revealed substantial heterogeneity with two or three molecular mass constituents, each being comprised by several isoelectric focusing variants. This heterogeneity could not be reduced by enzymatic deglycosylation. By contrast, proteolytic removal of a small (M _r 1000–4000) fragment from the chain resulted in the generation of a M _r 36 000 fragment, common to all the molecular mass variants. Unlike the parent proteins, the M _r 36 000 fragment derived from isolated variants yielded identical, simple patterns in two-dimensional gel electrophoresis and identical finger prints in peptide mapping. This, together with N-terminal amino acid sequencing, as well as comparison of hydrophobicity properties of fragments obtained by gradual proteolytic digestion, indicated that the small peptide responsible for the major B-F heterogeneity was situated in the intracellular, C-terminal part.     

The cya gene region of Erwinia chrysanthemi B374: organisation and gene products

Summary A DNA fragment containing the cya gene region of Erwinia chrysanthemi, B374 was cloned in vivo and transferred into cells of E. coli using a plasmid pULB113 derived from RP4 followed by subcloning in vitro into the vector pBR322. The cya gene encodes a 95 kDal protein that complemented E. coli cya mutants. Apparently, cya genes truncated at the 3 end could still produce proteins complementing cya-defective strains, thus showing that adenylate cyclase truncated at its carboxy-terminal end could synthesise cAMP. A protein of unknown function (40 kDal) is encoded by a gene that is transcribed divergently from the control region of the adenylate cyclase gene.     

Optimal age at sexual maturity of sympatric and experimentally allopatric cutthroat trout and Dolly Varden charr

Summary Reproductive potentials of transplanted curthroat trout (Salmo clarki) and Dolly Varden charr (Salvelinus malma) and of their donor stocks were estimated from life history data. We found good agreement between observed and predicted age at maturity in all populations, and cannot reject the hypothesis that the fish matured at the age maximizing the overall lifetime reproductive potential ( ). Our estimates were insensitive to probable variations in female fecundity, adult mortalityrate and maximum body length. Small changes in either juvenile mortality-rate or individual growth-rate had marked effects on the estimations, as did changes in the Malthusian parameter (r). Three alternative mechanistic explanations of how age at maturity is determined could be rejected. We suggest that fish are able to adjust the maturity age non-genetically to changes in growth-rate, and that temporal variations in juvenile survival-rate allow coexistence of genotypes coding for different ages at maturity at the same growth-rate.     

Release of ( 3 H)noradrenaline and ( 3 H)dopamine from field stimulated cerebral cortex slices. Effect of tyrosine hydroxylase and dopamine- -hydroxylase inhibition

Rat cerebral cortex slices were incubated in vitro with [³H]dopamine (DA) or [³H]noradrenaline (NA) (10^?7M), superfused by fresh buffer and stimulated by an electric field. The stimulation-induced overflow of [³H]DA and [³H]NA was determined. In slices from untreated rats about 16 ng [³H]NA/g tissue was formed from [³H]DA, corresponding to about 5 per cent of the endogenous NA concentration. Stimulation markedly enhanced the overflow of [³H]NA. The [³H]NA newly formed from [³H]DA was overflowing to a greater extent than [³H]NA previously taken up from the incubation medium, indicating a preferential release of newly synthesized transmitter. The stimulation-induced overflow of [³H]DA and [³H]NA was increased in slices of rats pretreated with a tyrosine hydroxylase inhibitor (H44/68). It seems that depletion of the endogenous NA stores of central NA neurons by tyrosine hydroxylase inhibition makes the [³H]cate-cholamines more available for release. Pretreatment of the rats with the DA-β-hydroxylase inhibitors FLA63 or FLA69 considerably diminished the formation of [³H]NA from [³H]DA. Stimulation markedly enhanced the overflow of [³H]DA indicating that DA can act as a ‘false transmitter’ in central NA neurons after DA-β-hydroxylase inhibition.